Closing device in a plastic injection molding machine

Abstract

A closing device in a hydraulic injection molding machine includes at least one pressure cylinder unit for building up locking pressure and a drive cylinder mounted in the pressure piston of the pressure cylinder unit for closing the injection mold. The drive cylinder is arranged concentrically relative to the central axis of the pressure cylinder unit. A support element for the pressure cylinder is jutted out by at least one cylinder of the mold closing unit on the side opposite to the stationary mold carrier, the cylinder being connected to the support element and stationary as a result thereof. The support element forms thereby a single piece with the stationary cylinder of the mold closing unit that is connected to the support element. This provides a space-saving structure that meets precision requirements for the production of injection molded parts.

1. Closing device on a mould closing unit of a plastic injection molding machine for processing plastics materials and other plasticizable substances, the closing device comprising:
 at least one hydraulic pressure cylinder unit for building up a closing pressure onto an injection mould accommodated in a mould clamping area between a movable mould carrier and a stationary mould carrier, 
 a pressure piston disposed in the at least one pressure cylinder unit, and comprising a piston rod disposed along a central axis of the at least one pressure cylinder unit, said pressure piston separating a high pressure chamber of the at least one pressure cylinder unit from a low pressure chamber of the at least one pressure cylinder unit wherein the high pressure chamber is arranged between the pressure piston and the movable mould carrier, 
 a hydraulic drive cylinder associated with the at least one pressure cylinder unit for closing the injection mould and disposed concentrically relative to said central axis, wherein a cylinder of the hydraulic drive cylinder is formed by the pressure piston of the at least one pressure cylinder unit, 
 a supporting element for supporting the at least one pressure cylinder unit, wherein at least one cylinder of the mould closing unit is fixedly connected to the supporting element on a side remote from the mould clamping area, 
 wherein the supporting element and the at least one cylinder of the mould closing unit are one piece, and wherein the supporting element is connected to the at least one cylinder of the mould closing unit. 
 
   
   
     2. Closing device according to  claim 1 , wherein the supporting element is mounted via a stationary bearing arrangement on a machine base or on a part thereof, and in that the at least one cylinder is also stationary. 
   
   
     3. Closing device according to  claim 1 , wherein the at least one cylinder being unitary with the supporting element is adapted to be a hydraulic compensating cylinder associated with the at least one pressure cylinder unit for accommodating hydraulic media coming out of the at least one pressure cylinder unit or respectively discharging hydraulic media to be deposited in the at least one pressure cylinder unit, a compensating cylinder chamber of the hydraulic compensating cylinder being in open connection with the low pressure chamber of the at least one pressure cylinder unit, wherein the hydraulic compensating cylinder is disposed concentrically relative to the central axis. 
   
   
     4. Closing device according to  claim 1 , wherein a piston rod of a compensating cylinder is formed by a cylinder of the at least one pressure cylinder unit. 
   
   
     5. Closing device according to  claim 4 , wherein the pressure piston and the piston rod of the at least one pressure cylinder unit are stationary and are connected to the at least one cylinder, and wherein the piston rod of the hydraulic compensating cylinder and consequently the cylinder of the at least one pressure cylinder unit is connected to a movable mould carrier for common movement. 
   
   
     6. Closing device according to  claim 1 , wherein the at least one cylinder being unitary with the supporting element is adapted to be a hydraulic compensating cylinder comprising a piston having an overflow channel for open connection between a compensating cylinder chamber and the low pressure chamber of the at least one pressure cylinder unit. 
   
   
     7. Closing device according to  claim 1 , wherein the at least one cylinder being unitary with the supporting element is adapted to be a hydraulic compensating cylinder surrounding the at least one pressure cylinder unit. 
   
   
     8. Closing device according to  claim 1 , wherein in the pressure piston of the at least one pressure cylinder unit there is provided a further overflow channel between the low pressure chamber and the high pressure chamber closable by a valve. 
   
   
     9. Closing device according to  claim 8  wherein the valve is formed by an annular piston, which is displaceable in a limited manner on the piston rod or respectively in the pressure piston of the at least one pressure cylinder unit. 
   
   
     10. Closing device according to  claim 3 , wherein the low pressure chamber and the compensating cylinder chamber are adapted to be put under additional pressure via a hydraulic line. 
   
   
     11. Closing device according to  claim 1 , wherein the at least one pressure cylinder unit is one single pressure cylinder unit comprising a central axis that is at the same time a central axis or respectively an axis of symmetry of the mould closing unit. 
   
   
     12. Closing device according to  claim 1 , wherein a locking pin provided on the pressure piston is adapted for opening a connection between the low pressure chamber and the high pressure chamber when actuated by a piston of a compensating cylinder. 
   
   
     13. Closing device according to  claim 1 , wherein the supporting element or the cylinder that is unitary with the supporting element has connection elements for the connection of at least one hydraulic distribution block.